The present invention relates to a method for imparting improved touch or feeling to a fabric and composition comprising an organopolysiloxane used therefor. More particularly, the invention relates to a novel method for imparting excellent touch or feeling of softness, smoothness and sliminess to various kinds of organic fibrous materials or fabrics not only of synthetic fibers but also of natural fibers, e.g. cotton, as well as blended yarn fabrics thereof by use of an organopolysiloxane-containing composition hitherto not used for such a purpose.
As is well known, there are widely used various types of fabric-finishing agents in the art such as waxes, alkylketene dimers and octadecylethylene urea as well as softeners containing a cationic surface active agent with an object to impart improved touch of smoothness or softness to fabric products. The fabric-finishing agents also include several types of compositions comprising an organopolysiloxane as the effective ingredient. Such an organopolysiloxane-containing composition is recommended when improvement is desired in respect of the water-repellency, softness, elasticity and tear strength.
Most of the organopolysiloxane-containing fabric-finishing agents comprise an organopolysiloxane fluid as the base ingredient, a cross-linking agent, a catalyst for accelerating the crosslinking reaction and other optional additives. When the organopolysiloxane-containing composition, prepared by blending together all of the components in advance, is unstable and poorly storable due to the premature gelation or other denaturation, the composition is prepared in two or more separate packages each containing a different component or a different combination of the components from the other and the contents of the packages are blended together directly before use for the treatment of the fabrics, on which crosslinking or curing of the organopolysiloxane is to be effected to exhibit the desired improvement in the fabric properties. Such a two- or multi-package crosslinkable type organopolysiloxane-containing composition is less preferred to the one-package type premixed ones due to the lower working efficiency even by setting aside the problem that the improvement obtained with such a composition is sometimes unsatisfactory in respect of the exquisite slipperiness in the touch of the treated fabrics.
There are also known and used organopolysiloxane compositions of non-crosslinking type for the fabric treatment. The mechanism of the improvement of the fabric properties obtained with such a composition is the decrease in the coefficient of friction between the filaments of the fabric by virtue of the layer of the oily organopolysiloxane adhering to the filament surface whereby to facilitate the relative movement of the filaments resulting, as a consequence, in the improvement of the fabric touch such as the softness. The organopolysiloxanes suitable for the formulation of such an organopolysiloxane composition of the non-crosslinking type are exemplified by dimethylpolysiloxanes, diorganopolysiloxanes modified with long-chain alkyl groups or epoxy groups and diorganopolysiloxanes modified with amino groups as are described in Japanese Patent Publications 48-1480 and 54-43617.
One of the problems in the softening treatment by use of the organopolysiloxane composition of the above described type is that sufficient effect of improvement can hardly be obtained in respect of the smoothness and softness of the treated fabric when the fabric is made of pure cotton although considerably satisfactory results can be obtained in the softening treatment of fabrics of a synthetic fiber, e.g. nylon and polyester, or blended yarn fabrics of cotton and these synthetic fibers. Further problem of the prior art silicone-based softening agent for fabric finishing is the relatively poor durability of the softening effect imparted by the treatment therewith when the treated fabric is laundered.